Plastic bottle and base cup for a pressurized dispensing system

ABSTRACT

A container for a pressurized dispensing system. The container includes a plastic bottle and a base cup bonded to a rounded bottom of the plastic bottle with a hot melt adhesive. The base cup has a bottom surface that allows the container to stand upright. A method of forming the container is also provided wherein hot melt adhesive is deposited in a recessed region in a top wall of a pedestal of the base cup, and a center region of the rounded bottom of the plastic bottle is pressed against the hot melt adhesive such that the adhesive spreads out over the recessed region and the rest of the top wall of the pedestal. After the hot melt adhesive cools, the bottle is securely bonded to the base cup.

BACKGROUND Field of the Invention

Our invention generally relates to a pressurized dispensing system, suchas a system that dispenses an aerosol product. More specifically, ourinvention relates to a dispensing system that includes a plastic bottlecontaining a product under pressure, with a base cup being attached tothe plastic bottle to allow the system to stand upright.

Related Art

Pressurized dispensing systems, such as systems used to dispense aerosolproducts, have conventionally included metallic (e.g. steel or aluminum)containers for containing the product under pressure before it isdispensed from the system. Examples of products that are dispensed withsuch systems include air fresheners, fabric fresheners, insectrepellants, paints, body sprays, hair sprays, shoe or footwear sprayproducts, whipped cream, and processed cheese. Recently, there has beenincreased interest in using plastic bottles as an alternative tometallic containers in pressurized dispensing systems because plasticbottles have several potential advantages. For example, plastic bottlesmay be easier and cheaper to manufacture than metallic containers, andplastic bottles can be made in a wider variety of interesting shapesthan metallic containers.

One of the biggest challenges in manufacturing plastic bottles forpressurized dispensing systems is providing the plastic bottle withenough structural integrity be able to withstand the internal pressurerequired for full evacuation of the product. For example, an internalpressure required for compressed gas aerosols generally ranges from 45PSIG to 200 PSIG at 70° F. whereas liquefied gas aerosols generallyranges from 17 PSIG to 108 PSIG at 70° F. If the plastic aerosol bottleis not provided with enough structural integrity to withstand suchpressurization through the life of the dispensing system, then there isa risk that the plastic aerosol bottle could rupture. In this regard, itis known that the pressure inside a plastic bottle can weaken theplastic structure over time, for example, by creating stress crazes andcracks in the plastic. Moreover, a pressurized dispensing system mightbe subject to an event that tests the structural integrity of itsplastic bottle, for example, when the bottle is dropped, or when thebottle is left in a high temperature environment that heats the contentsof the bottle to thereby increase the already high internal pressure.And the potential of a pressurized plastic bottle rupturing as a resultof any of these events presents a clear safety risk to users of thedispensing system.

From a user functionality standpoint, the ability of a dispensing systemto stand upright is very important. But, the use of a plastic bottle ina pressurized dispensing system presents a challenge with respect tomaking the system be able to stand upright. While the base of theplastic bottle could be molded in a flat shape that allows the bottle tostand upright, it has been found that imparting such a flat shape oftencreates problems. For example, contours that result from forming avertically stable base in the bottle may be highly susceptible to stresscrazing and cracking. Further, a contoured base may be prone to burstingif the plastic bottle is dropped, and the base may deform if thepressure inside the plastic bottle increases, e.g., in elevatedtemperature environments.

It has been found that a rounded base in a plastic bottle of apressurized dispensing system is far less susceptible to stress crazingand cracking then contoured bases. Further, as compared to a contouredbase, a rounded plastic base in a plastic bottle is less prone tobursting when dropped and less easily deformed in elevated temperatureswhen the bottle is filled with a product and pressurized. But, on theother hand, a rounded base does not provide a surface for making theplastic bottle stand upright. Thus, a secondary piece, or “base cup,”can be attached to the rounded bottom of a plastic bottle, with the basecup providing a flat surface that allows the plastic bottle to standupright.

While a base cup is conceptually an easy solution for making a plasticbottle with a rounded bottom stand upright, in practice attaching a basecup to a plastic bottle as part of a pressurized dispensing system is atremendous challenge. The pressurized dispensing system will likely beexposed to handling and different environments before ever reaching theend consumer. And, during handling or in different environments, thepressurized dispensing system may encounter conditions that may weakenthe attachment between the base cup and bottle, such as varyingtemperatures and impacts. If the attachment is weakened, the base cupmight later become detached from the bottle when being used by the endconsumer. It is critical that this does not happen—separation of thebase cup and bottle will at least result in unsatisfied consumers, ifnot result in significant safety hazards for the consumers.

While there are several techniques that could conceivably be used tosecurely attach a base cup to a plastic bottle, there are problems withmost of these techniques, particularly in the context of pressurizeddispensing systems. For example, while welding techniques such as sonic,vibration, laser, and spin welding might be used to tightly attach abase cup to the bottle, the heat generated during the welding softensthe material to a molten state, which in turn could lead to problematicstress risers when the bottle is subsequently filled with a product andpressurized. Additionally, welding plastics requires similar plasticfamilies to be used for both the base and base cup, which limits theresins that can be used. Another way that a base cup might be attachedto the bottom of a plastic bottle is through some method of mechanicalattachment, for example, the bottom of the bottle could be molded in ashape that locks to the base cup. However, such shaping of the bottom ofthe bottle may lead to the same types of problems that are found whenthe bottom of the bottle is made flat to make the bottle stand uprighton its own.

As an alternative to welding and mechanical attachments, adhesives mightbe used to attach the base cup to the plastic bottles. And while thereare many types of adhesives that might be considered, many of theseadhesives are not suited for use in conjunction with a plastic bottle ina pressurized dispensing system. For example, UV cured glues shrink whencured, which would put additional stress points on the plastic bottle,thereby leading to stress crazing or stress cracking. As anotherexample, solvent based structural adhesives, such as some epoxies, maynot be suitable because these adhesives are generally difficult to cureand have poor impact resistance.

SUMMARY OF THE INVENTION

According to one aspect, our invention provides a container for apressurized dispensing system. The container comprises a bottleincluding an opening at a top end and a rounded bottom at a bottom end,with the bottle being molded from a plastic material. The container alsoincludes a base cup adhered to the rounded bottom of the bottle with ahot melt adhesive, with the base cup including a pedestal adjacent to acenter of the rounded bottom of the bottle, and with the base cup havinga flat bottom surface that allows the container to stand upright. Thehot melt adhesive forms a layer between the pedestal and the roundedbottom of the bottle, with the hot melt adhesive being spread over thepedestal to thereby form an adhesive layer that prevents contact betweenthe rounded bottom of the bottle and the pedestal.

According to another aspect, our invention provides a method of forminga pressurized dispensing system. The method includes heating a hot meltadhesive such that the hot melt adhesive is in a molten state, anddepositing the molten melt adhesive in a recessed region in a top wallof a pedestal in a base cup. The method also includes pressing a centerregion of a rounded bottom of a plastic bottle against the molten hotmelt adhesive such that the molten hot melt adhesive spreads out overthe recessed region and the rest of the top wall of the pedestal, andcooling the molten hot melt adhesive to to thereby attach the base cupto the plastic bottle.

According to yet another aspect, our invention provides an aerosoldispensing system. The system includes a bottle having an opening at atop end and a rounded bottom at a bottom end, with the bottle beingformed from a plastic material, and with the bottle containing anaerosol product under pressure. A spray mechanism is attached to the topend of the bottle, with the spray mechanism including a nozzle throughwhich the aerosol product can be discharged. A base cup is adhered tothe rounded bottom of the bottle with a hot melt adhesive, with the basecup including a pedestal adjacent to a center of the rounded bottom ofthe bottle, and the base cup having a flat bottom surface that allowsthe aerosol dispensing system to stand upright. The hot melt adhesiveforms a layer between the pedestal and the rounded bottom of the bottle,with the hot melt adhesive being spread over the pedestal to prevent therounded bottom of the bottle from contacting the pedestal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a plastic bottle for use in a pressurizeddispensing system according to an embodiment of our invention.

FIG. 2 is an elevation view of the upper side of a base cup according toan embodiment of our invention.

FIG. 3 is a top view of the base cup shown in FIG. 2.

FIG. 4 is a cross-sectional view of a base cup shown in FIG. 2 as takenalong line 4-4.

FIG. 5 is a bottom view of the base cup shown in FIG. 2.

FIG. 6 is an elevation view of the lower side base cup shown in FIG. 2.

FIG. 7 is a cross-sectional view of the base cup shown in FIG. 2 astaken along line 4-4, with an adhesive applied to the base cup.

FIG. 8 is a cross-sectional view of a base cup shown in FIG. 2 as takenalong line 4-4, with the base cup being adhered to the bottom of aplastic bottle according to an embodiment of our invention.

FIG. 9 is a side view of a pressurized dispensing system according to anembodiment of our invention.

FIG. 10 is a cross-sectional view of the pressurized dispensing systemshown in FIG. 9 as taken along line 10-10.

DETAILED DESCRIPTION OF THE INVENTION

Our invention generally relates to pressurized dispensing systems. Morespecifically, our invention relates to a dispensing system that includesa plastic bottle containing a product under pressure, with a base cupbeing attached to the plastic bottle to allow the system to standupright.

In the descriptions that follow, we will sometimes explain features ofour invention in the specific context of an aerosol dispensing system.Those skilled in the art will readily appreciate, however, that ourinvention is not limited to use with aerosol products. Rather, thepressurized dispensing systems described herein could alternatively beused in conjunction with products other than aerosols. For example, thedispensing systems described herein might be used to dispense foamproducts such as shaving cream or soap, or used to dispense foodproducts such as soda, whipped cream, or processed cheese.

FIG. 1 is a side view of a plastic bottle 100 for use in a pressurizeddispensing system according to an embodiment of our invention. Thebottle 100 includes an upper end 102, a lower end 106, and a bodysection 104. At the upper end 102 is a neck region 108 having a crimpingring 110 surrounding an opening 112 of the bottle 100. The body section104 extends downward from the neck region 108 to the lower end 106 ofthe bottle 100. At the lower end 106, the bottle 100 is provided with arounded bottom 114. It should be noted that the shape, size, andproportions of the bottle 100 shown in FIG. 1 are merely exemplary.Indeed, one of the advantages of using plastic to form the bottle 100 isthat the plastic may be molded into a wide variety of shapes and sizes.In this regard, the bottle 100 may be formed using injection and/or blowmolding techniques, which are well known in the art. In such techniquesa plastic preform is first formed using injection molding; the plasticpreform is subsequently heated and stretch blow molded into the finalshape of the bottle 100.

A spray mechanism (not shown) including a valve structure may beprovided to the upper end 102 of the bottle 100, with the spraymechanism being crimped onto the crimping ring 108. Such a spraymechanism includes a nozzle through which product from the bottle isdispensed, for example, as an aerosol mist. These types of spraymechanisms are well known in the art. And along these lines, it will beappreciated by those skilled in the art that the upper end 102 of thebottle 100 may have a different configuration than as shown in order toaccommodate other types of spray mechanisms. For example, the bottlemight be configured without the crimping ring 100, with the spraymechanism being crimped to the inside of the neck region 108 of thebottle 100 at a position adjacent to the opening 112.

The lower end 106 of the bottle 100 includes a rounded bottom 114. Asused herein, the term “rounded” means that the bottom 114 is curved overthe area at the lower end 106 of the bottle 100. That is, a “rounded”bottom includes shapes that could be described as spherical, elliptical,domed, etc. As generally discussed above, the rounded bottom 114 isadvantageous compared to other shapes because the rounded bottom 114 isless susceptible to problematic stress crazing and cracking when thebottle is filled with a product and pressurized. For example, therounded bottom 114 does not include contours that would be required toform a self-standing bottle. The round shape of the bottom 114 providesother advantages as well. For example, as the plastic is formed into therounded shape during a blow molding process, stretch crystallinity isformed in the polymers making up the plastic.

Further, the gate in an injection mold used to form a preform of thebottle may be provided at a position corresponding to the center of therounded bottom 114, which leads to the center being the thickest sectionof the rounded bottom 114. By being the thickest section, the centerwill expand the least when the bottle is pressurized with a product,making the center of the rounded bottom 114 a good location for applyingan adhesive to connect a base cup, as will be described in detail below.

The bottle 100 may be formed from a wide variety of plastics. Someexamples of such plastics include branched or linear polyethyleneterephthalate (PET), polycarbonate (PC), polyethylene naphthalate (PEN),polyethylene furanoate (PEF), polyolefins (PO) such as polyethylene (PE)and polypropylene (PP), and other polyesters, and blends thereof.

FIGS. 2-6 are views of a base cup 200 according to an embodiment of ourinvention. The base cup 200 is configured to be attached to the roundedbottom 114 of the bottle 100, as will describe in detail below. The basecup 200 includes a side wall 202 defining an outer perimeter of the basecup 200. At the bottom of the base cup 200, a bottom wall 204 extendsinward from the cylindrical wall 202, with a plurality of apertures 206being formed in the bottom wall 204. A pedestal 208 projects upwardlyfrom the bottom wall 204 and within the space enclosed by thecylindrical side wall 202. More specifically, the pedestal 208 is formedwith a cylindrical wall 210 that extends from the bottom wall 204 to atop wall 212. A recessed area 214 is formed in the top wall 212.

The base cup 200 may be an injection molded resin, thermoformed, orstretch blow molded. Examples of polymeric resins that could be used toform the base cup 200 include PET, PEN, PEF, polypropylenes,polyethylenes, polyesters, polycarbonates, nylons, poly(vinyl chloride)and polystyrenes. Some specific examples of commercially availableresins that could be used to form the base cup 200 include FHRPolypropylene P5M6K-048 (a polypropylene copolymer) by Flint HillsResources of Wichita, Kans., PETROTHENE® NA206000 (a low densitypolyethylene) by LyondellBasell Industries of Northbrook, Ill., andDURASTAR' DS1910HF (a copolyester) by Eastman Chemical Company ofKingsport, Tenn. Ultimately, those skilled in the art will recognizethat the selection of the material for forming the base cup 200 willdepend on several factors, including cost and appearance (e.g., acolored resin versus a clear resin). The selection of the material forforming the base cup 200 may also depend on characteristics of thesurfaces of the base cup, as will be discussed in detail below.

FIGS. 7 and 8 show the application of an adhesive 300 to the pedestal208 of the base cup 200 and the subsequent attachment of the bottle 100to the base cup 200. This process starts with an adhesive 300 beingdeposited in the recessed area 214 of the pedestal 208. The adhesive 300may be applied with a single deposit or multiple deposits in therecessed area 214. As will be discussed below, the adhesive 300 is a hotmelt, meaning that it is heated to a liquid state and applied to thebase cup 200 in that liquid state. The rounded bottom 114 of the bottle100 is subsequently brought into contact with the adhesive 300, whichcauses the adhesive 300 to spread out over the recessed area 214 and thetop wall 212 of the pedestal 208. The adhesive 300 is then allowed tocool, with the bottle 100 thereby becoming firmly attached to the basecup 200 by the adhesive 300. The apertures 206 in the bottom wall 204 ofthe base cup 200 increase the speed which the adhesive 300 cools byallowing air to flow to the inside of the base cup 100 where the bottle200 is attached.

In the attachment process the adhesive 300 is applied to the base cup200 first, as opposed to being applied to the bottle 100. The adhesive300 may therefore cool slightly before it contacts the bottle 100. Thisis important because a temperature spike on points of the plastic of thebottle 100 where the adhesive 300 would be applied could potentiallysoften the plastic and thereby weaken the bottle 100. That is, if theadhesive 300 was applied first the bottle 100, the area of the bottle100 that contacts the adhesive might be susceptible to stress crazingand stress cracking when the bottle 100 is filled with a pressurizedproduct. The slight cooling of the adhesive 300 while the adhesive isfirst applied to the base 200 reduces the risk of the adhesive 300damaging the bottle 100.

By configuring the pedestal 208 with a recessed area 212, the base cup200 can accommodate a small range of the sizes of the bottle 100, e.g.,variances arising from manufacturing tolerances in molding the bottle100. Further, the recessed area 212 is formed around the center of therounded bottom 114 of the bottle 100. As discussed above, the bottle 100may be formed in a process where a preform is injection molded, withinjection gate corresponding to the center of the rounded bottom 114 inthe bottle 100 ultimately formed in the process. Such a configurationresults in a slight bulge being formed at the center of the roundedbottom 114. The recessed area 212 of the pedestal 208 can accommodatesuch a bulge at the center of the rounded bottom 114.

As shown in FIG. 8, the adhesive 300 spreads out evenly over recessedarea 214 and the top wall 212 of the pedestal 208 such that there is alayer of adhesive 300 between the pedestal 208 and the rounded bottom114 of the bottle 100. That is, the adhesive 300 make it such that thereis little, if any, contact between the pedestal 208 of the base cup 200and the rounded bottom 114 of the bottle 100. That the layer of adhesive300 separates the pedestal 308 and the rounded bottom 114 is highlyadvantageous because contact points between the pedestal 208 and roundedbottom 114 are in effect weak spots that increase the risk of the basecup 200 separating from the bottle 100, for example, during an impact; astrong bond is formed between the base cup 200 and the bottle 100 whenthe adhesive 300 is spread out over the entirety of the area between thepedestal 208 and the rounded bottom 114. Factors that can be adjusted toensure that the adhesive 300 spreads out over the pedestal 208 will bediscussed in detail below.

There are a wide variety of adhesives that could potentially be used toattach the base cup 200 to the bottle 100. But, as discussed above, sometypes of adhesives (such as UV cured glues and solvent based structuraladhesives) have properties that are not suited for use in a pressurizeddispensing system. Hot melt adhesives, however, do have severalproperties that facilitate the attachment of a base cup to a plasticbottle in a pressurized dispensing system. In particular, we have foundthat hot melt adhesives with a low surface energy work well to attachthe base cup 200 to the bottle 100 in the process describe above. Suchhot melt adhesives have elastic-like properties that impart impactresistance to the system. Further, such hot melt adhesives are flexiblesuch that the base cup 200 can remain firmly attached to the bottle 100even as the bottle 100 expands and contracts. Still further, a hot meltadhesive provides minimal stress when the adhesive is applied to thebase cup 200 and bottle 100. That is, because these adhesives can beapplied at a lower temperature, the adhesives are less likely tooverheat the base cup 200 and bottle 100, and as such, the base cup 200and/or bottle 100 can be made thinner without risking that they willmelt during the attachment process. And the low melting temperature ofthe adhesive 300 means that the adhesive will more quickly cool to thefinal, adhered state. Hot melt adhesives also induce less stress on thebottle 100 than other types of adhesives from the standpoint thatshrinkage of hot melt adhesives is negligible as the adhesives arecooled. A further property of hot melt adhesives that is beneficial isthe green strength of such adhesives, green strength being the abilityof an adhesive to hold before it is cured. Still further, hot meltadhesives can quickly set, with a 75 to 100 percent adhesive strengthbeing achieved after only a few seconds of drying.

One of the significant properties of the hot melt adhesive 300 is itsviscosity at the time it is applied to the base cup 200. As discussedabove, the adhesive 300 spreads out over the recessed area 214 and thetop wall 212 of the pedestal 208. If the viscosity of the adhesive 300is too high, the adhesive 300 may not spread out over the area asintended. On the other hand, if the viscosity of the adhesive 300 is toolow, the adhesive 300 may spread out too much and spill out over theedge of the top wall 212. In either case of the viscosity of theadhesive 300 being too high or too low, the result is insufficientadhesive 300 coverage of the surface area between the pedestal 208 andthe rounded bottom 114 of the bottle 100. This means that there will beless adhesion between the base cup 200 and the bottle 100—the base cup200 may in turn easily separate from the bottle 100 when it is pulled,pealed, or when it is dropped. Through experiments we found that a hotmelt having a viscosity of 2500 to 5000 cps at application temperaturecan effectively spread out over the pedestal 208 as described herein.With a viscosity in this range, the hot melt adhesive 300 spreads evenlyaround the recessed area 214 and the top wall 212, and an even bead ofadhesive 300 is formed around the edge of the top wall 212 adjacent tothe cylindrical wall 210.

The surface energy of the pedestal 208 is another factor that affectshow the adhesive 300 will spread out on the pedestal 208. The materialfrom which the surfaces of the pedestal 208 are constructed will havesome inherent surface energy that may, or may not, facilitate thespreading of the adhesive 300—the adhesive 300 will more easily spreadout on a surface that has a higher surface energy than a surface thathas a lower surface energy. When the surfaces of the base cup 200 do nothave a desired surface energy, the surfaces may be modified to increasespreading of the adhesive 300. For example, roughening the top wall 212and the recessed area 214 creates crevices that allow the adhesive 300to bite into and thereby more easily spread out over the surfaces. Aswill be appreciated by those skilled in the art, the surfaces of the topwall 212 and the recessed area 214 can be made rougher in a process ofmolding the base cup 200, or the surfaces could be made rougher aftermolding the base cup 200. Another example of a treatment that could beapplied to the surfaces of the top wall 212 and the recessed area 214 toincrease spreading of the adhesive is corona treating.

In such a process, a high voltage discharge is directed to the surfacesthat are to be modified (i.e., the surfaces of the top wall 212 and therecessed area 214). The result is that an increased chemical connectioncan be formed between the corona treated surfaces and the adhesive 300.We found that corona treatment significantly increased spreading of theadhesive 300 when the base cup 200 is formed from low densitypolyethylene.

Any modification of the properties of the surfaces of the pedestal 208may be selected in combination with the viscosity of the adhesive 300.That is, the surfaces of the pedestal 208 may be modified to achieve adesired spreading of the adhesive 300 in a case where the adhesive 300is set to have a particular viscosity at the time of its application.Alternatively, the viscosity of the adhesive 300 at the time ofapplication can be increased or decreased to achieve a desired spreadinggiven particular properties of the surface of the pedestal 208. In aspecific example, we found that when an adhesive having a viscosity of2500 to 5000 cps was used, a corresponding VDI 45 finish on the surfacesof the recessed area 214 and top wall 212 resulted in the adhesive 300being evenly spread over the surfaces so that a strong bond was formedbetween the base cup 200 and the bottle 100.

As to particular hot melt adhesives that can be used in our invention,we have found that solid based hot melt adhesives provide the bestcombination of properties for attaching the base cup 200 to the plasticbottle 100. Such adhesives are heated to the molten viscosity, with thehigher the heating temperature the lower resulting viscosity of theadhesives. These adhesives are applied in the molten state, and when theadhesives are cooled to form a bond. Notably, there is minimal shrinkageof these types of adhesives as they are cooled—the density of appliedadhesive is approximately the density of adhesive after cooling.

We specifically found that hot melt adhesives that are based onethylene-vinyl acetate (EVA) or polyamides provide good bonding betweenthe base cup 200 and the plastic bottle 100. Examples of such adhesivesare sold under the tradenames HM-302D by Ellsworth Adhesives ofGermantown, Wis., and SCOTCH-WELD™3792 LM and 3789Q by 3M of Maplewood,Minn. We particularly found that adhesives that include an acryliccomponent provide the best bonding between the base cup 100 and plasticbottle in embodiments of our invention. An example of such an adhesiveis comprised of EVA, an acrylic (which we believe to be poly(butlyacrylate) or poly(ethyl acrylate)), and polystyrene and is sold underthe tradename HMS-792 by Ellsworth Adhesives. Without being bound bytheory, we think that the combination of a hot melt component (e.g.,EVA) and an acrylic (e.g., poly(butly acrylate) or poly(ethyl acrylate))provides bondings at the molecular level between the base cup 200 andthe bottle 100, with the hot melt component providing a carrier for theacrylic that provides a van der Walls type bond.

The hot melt adhesives described herein are easy to work with. Theseadhesives are molten with a viscosity in the range of 2500 to 5000 cpsat temperatures around 225-400° F. Further, these hot melt adhesiveshave significant open times, i.e., the maximum amount of time after theadhesive is applied that a bond can be formed with additional pressurebeing applied. In this regard, we found that an acrylic hot meltadhesive had open time around 75 seconds, while other hot melt adhesiveshad open times of about 40 to about 50 seconds. With such extended opentimes, the hot melt adhesives can be applied to multiple base cups in aproduction line before bottles are brought into contact with theadhesives, thereby providing flexibility in the manufacturing process.

In alternative embodiments of our invention, other types of adhesivesmay be used to attach the base cup 200 to the bottle 100. For example, apressure sensitive adhesive might be used, such as EVA blended with astyrene block copolymer. An adhesive of this type is sold as H7911-334Bby Bostik of Paris, France. Another styrenic copolymer based adhesivethat could be used is H20182 by Bostik. Those skilled in the art willrecognize still other adhesives that would form a bond between the basecup 200 and the bottle 100 as described herein.

TABLE 1 shows tests that we conducted to determine the adhesive strengthbetween a base cup bonded to a plastic bottle in terms of the pull offforce required to separate the base cup and the bottle. In these teststhe plastic bottle was molded from PET, and the base cup was molded fromthe materials as indicated. The base cup and bottle had theconfigurations described above. The bottle and the base cup were sizedsuch that there was about 1.72 in² of adhesive area between the pedestalof the base cup and the rounded bottom of the bottle. Note, the UV curedadhesive DEVCON® TRU-BOND™ PB 3500 by ITW Performance Polymers ofDanvers, Mass., was tested for comparison to the hot melt adhesives.

TABLE 1 Amount of Pull Adhesive Force Adhesive (g) Base Cup Material(lbf) EVA + Acrylic + 0.95 Polypropylene Copolymer 85.90 Polystyrene(Flint Hills P5M6K-048) (Ellsworth HMS 792) EVA + Acrylic + 0.95 LowDensity 96.10 Polystyrene Polyethylene (Ellsworth HMS 792) (PETROTHENE ®NA206000) EVA + Acrylic + 0.95 Copolyester 152.00 Polystyrene(DURASTAR ™ (Ellsworth HMS 792) DS1910HF) EVA + Acrylic + 1.00Polypropylene Copolymer 107.00 Polystyrene (Flint Hills P5M6K-048)(Ellsworth HMS 792) Over-Heated EVA + Acrylic + 1.00 Low Density 97.60Polystyrene Polyethylene (Ellsworth HMS 792) (PETROTHENE ® Over-HeatedNA206000) EVA + Acrylic + 1.00 Copolyester 175.00 Polystyrene(DURASTAR ™ (Ellsworth HMS 792) DS1910HF) Over-Heated EVA + Polystyrene0.90 Polypropylene Copolymer 68.80 (SCOTCH-WELD ™ (Flint HillsP5M6K-048) 3792) EVA + Polystyrene 0.90 Low Density 28.30 (SCOTCH-WELD ™Polyethylene 3792) (PETROTHENE ® NA206000) EVA + Polystyrene 0.90Copolyester 95.00 (SCOTCH-WELD ™ (DURASTAR ™ 3792) DS1910HF) Polyamide0.90 Polypropylene Copolymer 55.50 (SCOTCH-WELD ™ (Flint HillsP5M6K-048) 3789Q) Polyamide 0.90 Low Density 41.20 (SCOTCH-WELD ™Polyethylene 3789Q) (PETROTHENE ® NA206000) Polyamide 0.90 Copolyester93.70 (SCOTCH-WELD ™ (DURASTAR ™ 3789Q) DS1910HF) EVA 0.90 PolypropyleneCopolymer 38.90 (Ellsworth HM-302-D) (Flint Hills P5M6K-048) EVA 0.90Low Density 3.80 (Ellsworth HM-302-D) Polyethylene (PETROTHENE ®NA206000) EVA 0.90 Copolyester 56.60 (Ellsworth HM-302-D) (DURASTAR ™DS1910HF) UV Cured Adhesive 0.30 Polypropylene copolymer 15.50(TRU-BOND ™ PB (Flint Hills P5M6K-048) 3500) UV Cured Adhesive 0.30 LowDensity 9.70 (TRU-BOND ™ PB Polyethylene 3500) (PETROTHENE ® NA206000)UV Cured Adhesive 0.30 Copolyester 45.20 (TRU-BOND ™ PB (DURASTAR ™3500) DS1910HF)

As can be seen from the data in TABLE 1, the hot melt adhesivecontaining EVA and an acrylic provided the strongest bond between thebase cup and the bottle. It should also be noted that all of the hotmelt adhesives provided at least comparable bonding to the UV curedadhesive. But, as discussed above, the hot melt adhesives areadvantageous over UV cured adhesives in other ways. For example, hotmelt adhesives do not shrink upon hardening, whereas UV cured adhesivesdo significantly shrink, which can harm the plastic structure of thebottle.

As generally discussed above, due to potential safety hazards, apressurized dispensing system must be able to withstand impacts withoutfailing. In this regard, U.S. Department of Transportation (DOT)regulations specifically require that a pressurized dispensing containermust be able to withstand being dropped from a height of 1.8 m both ontothe bottom of the container and when the container is angled at 45°relative to the ground. We applied DOT tests to the bottle and base cupcombinations shown in TABLE 1. We found that the base cup and bottlebonded together with the hot melt adhesives did not generally becomeseparated from the impact of the drop. We believe that the hot meltadhesives provide a flexible layer between the base cup and bottle thatdoes not fatigue as a result of the impact, and this flexing likelycontributed to the base cup remaining attached to the bottle in the droptests.

The combination of the bottle 100 and the base cup 200 can form acontainer for a pressurized dispensing system, such as a system fordispensing an aerosol product. An example of this type of pressurizeddispensing system 400 is shown in FIGS. 9 and 10. In the system 400, therounded bottom 114 of the bottle 100 is adhered with a hot melt adhesive300 to the pedestal 208 of the base cup 200. The base cup 200 allows thesystem 400 to stand upright on a flat surface despite the bottle 100having a rounded bottom 114. As discussed above, the adhesive 300creates a layer between the rounded bottom 114 and the pedestal 208. Assuch, the outer rim 216 is the only portion of the base cup 200 thatcontacts the bottle 100. Notably, in this embodiment the outer rim 216is positioned adjacent to the body section 104 of the bottle 100 suchthat the rounded bottom 114 cannot be seen. In other embodiments,however, the outer rim 216 is positioned lower on the bottle 100 suchthat a portion of the rounded bottom 114 can be seen. At the top of thesystem 400 of the bottle is a spray mechanism 402, as discussed above.The pressurized product contained within the bottle 100 is dispensedthrough the spray mechanism 402 in this case as an aerosol mist.Although not shown, a cap may be provided over the spray mechanism 402.In sum, the bottle 100 and base cup 200 provide for a convenient andattractive.

In a specific embodiment of our invention, the system 400 is used todispense an air freshening composition. Examples of formulations for theair freshening composition can be found in U.S. patent application Ser.No. 15/094,542, which is hereby incorporated by reference in itsentirety.

Although this invention has been described in certain specific exemplaryembodiments, many additional modifications and variations would beapparent to those skilled in the art in light of this disclosure. It is,therefore, to be understood that this invention may be practicedotherwise than as specifically described. Thus, the exemplaryembodiments of the invention should be considered in all respects to beillustrative and not restrictive, and the scope of the invention to bedetermined by any claims supportable by this application and theequivalents thereof, rather than by the foregoing description.

INDUSTRIAL APPLICABILITY

The invention described herein can be used in the commercial productionof a pressurized dispensing system. Such pressurized dispensing systemshave a wide variety of uses, for example, in the market of aerosolproducts.

1. A container for a pressurized dispensing system, the containercomprising: a bottle including an opening at a top end and a roundedbottom at a bottom end, the bottle being molded from a plastic material;and a base cup positioned adjacent to the rounded bottom of the bottle,the base cup including (i) a bottom surface that allows the container tostand upright and (ii) a pedestal provided around a center area of therounded bottom of the bottle, the pedestal including a top wall having afirst surface and a continuously curved second surface adjacent to thefirst surface, wherein a hot melt adhesive provided on the the firstsurface attaches the base cup to the bottle, wherein the center area ofthe rounded bottom of the bottle is spaced from the second surface ofthe base cup, and wherein a center axis of the bottle passes through thesecond surface of the base cup.
 2. The container according to claim 1,wherein the adhesive is spread over the second surface of the base cupand the rest of the top wall of the pedestal of the base cup.
 3. Acontainer for a pressurized dispensing system, the container comprising:a bottle including an opening at a top end and a rounded bottom at abottom end, the bottle being molded from a plastic material; and a basecup positioned adjacent to the rounded bottom of the bottle, the basecup including a bottom surface that allows the container to standupright and a pedestal provided around a center area of the roundedbottom of the bottle, the pedestal including a top wall, with a recessedarea being formed in the top wall, wherein a hot melt adhesive providedon the top wall attaches the base cup to the bottle, with the hot meltadhesive including an acrylic component, wherein the center area of therounded bottom of the bottle is spaced from the recessed area of thebase cup.
 4. The container according to claim 3, wherein the hot meltadhesive includes ethylene-vinyl acetate and the acrylic component. 5.The container according to claim 1, wherein the bottle is formed frompolyethylene terephthalate.
 6. The container according to claim 1,wherein the base cup is formed from a resin selected from the groupconsisting of polyethylene terephthalate, polypropylene, and polyester.7. The container according to claim 1, wherein a plurality of aperturesis provided in the bottom surface of the base cup.
 8. A method offorming a pressurized dispensing system, the method comprising: heatinga hot melt adhesive such that the hot melt adhesive is in a moltenstate; applying a plurality of deposits of the molten hot melt adhesiveto a pedestal of a base cup; positioning a rounded bottom of a plasticbottle adjacent to the base cup such that the rounded bottom of thebottle contacts the molten hot melt adhesive and a center area of therounded bottom of the bottle is spaced from an adjacent continuouslycurved surface of the pedestal, with a center axis of the bottle passingthrough the continuously curved surface; and cooling the molten hot meltadhesive to thereby attach the base cup to the plastic bottle in an areaof a top wall of the pedestal that is adjacent to the continuouslycurved surface of the pedestal.
 9. The method according to claim 8,wherein the molten hot melt adhesive forms a layer between the roundedbottom of the bottle and the pedestal of the base cup such that therounded bottom of the bottle does not contact the pedestal.
 10. Themethod according to claim 8, wherein the hot melt adhesive has aviscosity of 2,500 cps to 5,000 cps when it is applied to the pedestalof the base cup.
 11. The method according to claim 8, wherein the hotmelt adhesive is heated to a temperature of about 225° F. to about 400°F. when it is applied to the pedestal of the base cup.
 12. The methodaccording to claim 8, wherein the hot melt adhesive includes an acryliccomponent.
 13. The method according to claim 12, wherein the hot meltadhesive includes ethylene-vinyl acetate and the acrylic component. 14.An aerosol dispensing system comprising: a bottle including an openingat a top end and a rounded bottom at a bottom end, the bottle beingmolded from a plastic material, and the bottle containing an aerosolproduct under pressure; a spray mechanism attached to the top end of thebottle, the spray mechanism including a nozzle through which the aerosolproduct can be discharged; and a base cup positioned adjacent to therounded bottom of the bottle, the base cup including (i) a bottomsurface that allows the container to stand upright and (ii) a pedestalprovided around a center area of the rounded bottom of the bottle, thepedestal including a top wall having a first surface and a continuouslycurved second surface adjacent to the first surface, wherein a hot meltadhesive provided on the the first surface attaches the base cup to thebottle, wherein the center area of the rounded bottom of the bottle isspaced from the second surface of the base cup, and wherein a centeraxis of the bottle passes through the second surface of the base cup.15. The system according to claim 14, wherein the adhesive is spread onthe second surface of the base cup and the rest of the top wall of thepedestal of the base cup.
 16. The system according to claim 14, whereinthe hot melt adhesive includes an acrylic component.
 17. The systemaccording to claim 16, wherein the hot melt adhesive includesethylene-vinyl acetate and the acrylic component.
 18. The systemaccording to claim 14, wherein the bottle is formed from polyethyleneterephthalate.
 19. The system according to claim 14, wherein the basecup is formed from a resin selected from the group consisting ofpolyethylene terephthalate, polypropylene, and polyester.
 20. The systemaccording to claim 14, wherein a plurality of apertures is provided inthe bottom surface of the base cup.